documentation.configure.help

网上下到的一个很详细介绍VPN基础知识的资料

RCSID $Id: Documentation.Configure.help,v 1.9 2000/09/12 03:25:42 rgb Exp $
--- ./Documentation/Configure.help.preipsec	Sat Aug 28 02:16:15 1999
+++ ./Documentation/Configure.help	Sat Aug 28 02:24:58 1999
@@ -3530,6 +3530,59 @@
   This is a backward compatibility option, choose Y for now.
   This option will be removed soon.
 
+IP Security Protocol (IPSEC) (EXPERIMENTAL)
+CONFIG_IPSEC
+  This unit is experimental code.
+  Pick 'y' for static linking, 'm' for module support or 'n' for none.
+  This option adds support for network layer packet encryption and/or
+  authentication with participating hosts.  The standards start with:
+  RFCs 2411, 2407 and 2401.  Others are mentioned where they refer to
+  specific features below.  There are more pending which can be found
+  at:  ftp://ftp.ietf.org/internet-drafts/draft-ietf-ipsec-*.
+  A description of each document can also be found at: 
+  http://ietf.org/ids.by.wg/ipsec.html.
+  Their charter can be found at: 
+  http://www.ietf.org/html.charters/ipsec-charter.html
+  Snapshots and releases of the current work can be found at: 
+  http://www.freeswan.org/
+
+IPSEC: IP-in-IP encapsulation
+CONFIG_IPSEC_IPIP
+  This option provides support for tunnel mode IPSEC.  It is recommended
+  to enable this.
+
+IPSEC: Authentication Header
+CONFIG_IPSEC_AH
+  This option provides support for the IPSEC Authentication Header
+  (IP protocol 51) which provides packet layer sender and content
+  authentication.  It is recommended to enable this.  RFC2402
+
+HMAC-MD5 algorithm
+CONFIG_IPSEC_AUTH_HMAC_MD5
+  Provides support for authentication using the HMAC MD5
+  algorithm with 96 bits of hash used as the authenticator.  RFC2403
+
+HMAC-SHA1 algorithm
+CONFIG_IPSEC_AUTH_HMAC_SHA1
+  Provides support for Authentication Header using the HMAC SHA1
+  algorithm with 96 bits of hash used as the authenticator.  RFC2404
+
+IPSEC: Encapsulating Security Payload
+CONFIG_IPSEC_ESP
+  This option provides support for the IPSEC Encapsulation Security
+  Payload (IP protocol 50) which provides packet layer content
+  hiding.  It is recommended to enable this.  RFC2406
+
+3DES algorithm
+CONFIG_IPSEC_ENC_3DES
+  Provides support for Encapsulation Security Payload protocol, using
+  the triple DES encryption algorithm.  RFC2451
+
+IPSEC Debugging Option
+CONFIG_IPSEC_DEBUG
+  Enables IPSEC kernel debugging.  It is further controlled by the
+  user space utility 'klipsdebug'.
+
 SCSI support?
 CONFIG_SCSI
   If you want to use a SCSI hard disk, SCSI tape drive, SCSI CDROM or